1. Field of the Invention
This invention relates generally to a new polypeptide, its method of isolation, biological actions of the peptide, and its therapeutic usefulness. More particularly, the present invention relates to a new polypeptide isolated from the intestines of chickens or other fowl by means of novel purification procedures and to the wide-range of activity of the polypeptide which affect cardiovascular, respiratory and metabolic functions.
2. Description of the Prior Art
It is well-known that polypeptide hormones regulate many physiologic functions and mediate certain pathological responses. While numerous compounds have been known to possess a vasodilator effect, many possess this effect only to a relatively slight degree or for a very short time. Medical science has, therefore, sought materials exhibiting a more potent or sustained vasodilator effect which would be more useful therapeutic agents.
In earlier filed U.S. Pat. Applications Ser. No. 181,444, filed Sept. 17, 1971, now U.S. Pat. No. 3,879,371, and Ser. No. 417,605, filed Nov. 20, 1973, now U.S. Pat. No. 3,880,826, there is disclosed a vasoactive peptide and its method of isolation from the upper intestinal wall of porcine. The porcine vasoactive intestinal peptide was identified as an octacosapeptide of specific sequence which exhibited biological activity in the areas of systemic vasodilation, hypotension, increased cardiac output, respiratory stimulation and hyperglycemia. A report on this peptide and its method of isolation may be found in the literature in Science, 169, 1217-1218 (1970). Another publication of interest to the porcine vasoactive peptide may be found in Eur. J. Biochem., 42, (1974).
The present invention is concerned with a vasoactive octacosapeptide which has been isolated from the intestines of chickens and other fowl which is related to but distinctly different from the porcine peptide in structural sequence and biological activity.